ansi incomplete, but sholvs an cavelike overhang of the selenizone ancl an absence of ornament, near the suture. Lack of ornament, clistinguishes these specinlens fronl a Mississippian form in the. collections referrecl to Ph y»<atoplev>'a.

Illustrated. specin<en.— USN<>I 1805:''<", USGS locality 1008.

Occurrence nnd nbundnnce.— Ha<llerochit formation: ITSGS locality 100S, one; 15886, one.

Tribe EOTOMARIIDES
Genus BEMBEXIA Oehlert, 1SSS

Bembexiai inumbilicata Yochelson and Dutro, n. sp.
Plate 18, figures 80, 81

Dear">iptio><.— Large conical auonlphalous gastro- pods with borclerecl selenizone f orming periphery; earlier whorls unknown; sutures impressecl; body whorl embracing penultiurate whorl below periphery; upper whorl surface inclined outwarcl approziuiately

from vertical anil gently inRatecl, turning abruptly to horizontal ancl forlning the upper borclering Range of the selenizone at the periphery; whorl profile below selenizone inclined steeply clownwarcl for approxi- lnatelv one-half of its length, then curving more strongly inward to the anonq>halous base; concave selenizone locatecl on the periphery between strong borclering Ranges, the, ilpper Range overlranging the lower; lunulae faint,; growth lines prosocline fronl suture, approximately 90, bencling nlore abruptly backwarcl just, above the selenizone, below the seleni- zone opisthocline for a short distance then curving to prosocline, about, >O' fronl vertical„ancl continuing straight downwarcl; columellar lip with a narrow in- cluctura; ornament of inq>ressed growth lines alone.

Dis«zsssion.— Bern?>ezia,'? i><vml>ili<ata appears to be nlost siulilar, superficially, to T>ol>iriost>oph<z Long- stafi', 101>„but lacks both an unlbilicus and pitting in the shell. It ditTers froul Pe»<l>e,<ia larteti (Munier- Chahnas), the tvpe species, in being higher spired ancl in having the upper R:luge of the selenizone, rather than the louver Range, at the periphery. Because the significance. of these cliA'erences <.annot nolv be evalu- atecl, generic placenlent of the species is questionecl.

In aclclition to gross shape, Bembeziia'? <'><am?>ilicata, clitfers fronl Alaskan specimens referrecl to 3lo<zrlo><ia in lacking strong colabrll ornanlent. It lacks nocles on the upper surf <ce as are found in T'ociovpira or- ><ata. The species is ulost sinlilar in shape to speci- nlens leferrecl tolls New genus'? B., ancl at one, time the two foruls were, confusecl. They clitfer however in the nature of the umbilicus, B.'? i><v»«>>Vic'ata being clc"ll'lv 'lnonq)lra Ious.

The spire of the holotype is inconlplete and the aperture is slightly crushed. No lneauingful meas- urelnents of the species can be presentecl.

Ill><struted speci>nen,— Holotvpe: USNihI 18"586, USGS lo- cality 1086' .

Occur>'ence un<2 nbundnnce.— Alapah liinestone: UHGS lo- calitv 10S0', tivo; I'770, three; 14151, one; 1884'", one.

Genus GLABROCIEGULUM Thomas, 1940

Subgenus GLABROCIEGULUM Thomas 1940 Glabrocingulum (Glabrocingulum) sp.

Plate 18, figures 11 — 18

Disevssio><.— This species is representecl by two specinlens from the Siksikpuk fornlaticn. They are nloclerately low spired, conical, aud have the seleni- zone locatecl at the periphery. The upper whorl sur- face bear» a row of coarse, uodes at, the suture and at least three rolvs of fine nodes. The narrow seleni- zone is concave and borclered by share lirae. The ;lrched basal surface bears at, least seven spiral carinae, all of which are noclecl. The base is anouqlhalous. The species cloes not warrant, specihc nanling in view of the snlall number of specinlens avail"ble.

I<lust> «tcd speci>nen.— UHNM 18658<, USGS locality 14174.

Occurrence und. nbundnnce.— Sil;sihpuh for"iation: USGS locality 14174. two.

Subfamily EEIISOEIIEAE
Genus EEILSOEIA Thomas, 1940

Eeilsonia ) sp.
Plate 18, figure "-5

Discvssio><.— Two collections fronl northern Alaska contain snlall, moclerately high spired pleurotonlari- cean». All are, poorly preserved, but, enough remains of the shell to show the lnain features. The upper surface is clistinctly inclinecl, but, little archecl. The selenizone forlns the outer whorl face ancl is nearly vertical, the lower eclge being at the periphery. The selenizone proper is concave ancl clistinctly borclered. Below the selenizone the, basal whorl surface is nearly straight, inclinecl inwarcl for a clistance about, the iviclth of the selenizone, at, which place thelv is a clistinct though slight angulation, below which the basal v< horl surface curves inward ancl strongly clownwarcl. The base is auoznphalous. The colunlel- lar lip is slightly refiercecl. The upper whorl surface appears to lrave strong colabral ornanlealt. No speci- >Den is couq>lete einough to show all the. cletails given above, ancl a fornlal naule cloes not, appear ju»tifiecl.

Illustr«ted, spec»nen.— USNM 186588, USGH le< alitv 9184.

Occ><r> ence nnd nbundnncc.— Alapah liniestone: USGS lo- cality 0184, fifty; 10S68, twenty five.

LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA

139